Multipower shears



A. SHIRK MULTIPOWER SHEARS 'April 7, 1925.

Fil'ea Jan. 15, 1923 INVENTOR 7 Iii h.

WITNESSES ATTOR N EY Patented 7, 1925.

UNITED STATES Alanna SHIRK, or DECATUR, ILLINOIS.

MULTIPOWER SHEARS.

Application filed January 15, 1923. Serial No. 612,?60.

To all whom it may concern:

Be it known that I, Annnn SHIRK, a citizen of the United States, residing at Decatur, in the county of Macon and State of Illinois, have invented a new and useful Improvement in Multipower Shears, of which the following is a specification.

My invention relates to multi-power shears, and is-more particularly adapted for toolsof the type generally known as snips.

One of the important objects of the invention is to provide means for progressively increasing the multiplication of power between the handles andthe blades as the out approaches the points of the latter. In accomplishing this object, not only is the leverage 011 the movable blade progressively increased by increasing the distance between the power and the fulcrum, but the relative angular movement of the handle with respect to the pivotal movement of the blade progressively increases.

Another object of theinvention is to provide improved means which constantly acts upon the movable blade to urge it into closer engagement with the fixed blade.

The invention will be better understood from the following detailed description taken in connection with the accompanying drawing which illustrates the preferred structure by means of which the invention is carried out.

In the drawing Fig. 1 is a side elevation of the invention.

Fig. 2 is a perspective view thereof.

Fig. 3 is a transverse section taken on the line 33 of Fig. 1.

Fig. 4 is a transverse section on the line 44 of Fig. 1.

The invention comprises a pair of blades 5 and 6, which are pivotally connected at 7. The blade 5, which is relatively fixed, when the tool is in use, is extended beyond its pivot to form a comparatively long shank 8 and a handle 9 integral therewith, which is adapted to be engaged by the fingers of the operator. The other blade 6 is extended to form a comparatively short shank 10 which is provided with a curved slot 11. The handle 12, which is adapted to he engaged by the-thumb of the operator, is provided with a shank 13 having forwardly and inwardly extending ears 1st and 15 that extend on either side of the shank 8, and are pivotally connected thereto by means ofa pivot pin 16. The ears 1% and 15 are extended on the opposite sides of the shank 13, as indicated at 17 and 18, to form. in effect a bifurcated arm which carries a roller 19 that engages the slot 11' and travels back and forth in said slotwhen the handles are operated to actuate -the blades 5 and 6.

As the handle 12 is movedabout its pivot 16, power is applied to the shanklO of the blade 6, by means of the roller 19 traveling in the slot 11, and as the cut approaches the 1 outer ends of the blades, the point of application of the roller 19 travels away from the pivot 7 and thereby increases the leverage'on the shanltlO. It will also be noted that the slot 11 is curved withits concaved side towardthe fixed shank 8, and, the radius of curvature of said slot progressively increases toward the end nearest the handle so that as the bladesapproach closed position and the cut progresses toward the points thereof, the relative angularmovement of the handle with respect to the angular movement of the blade *6 will be increased. Thus, the angle between the path of the roller and the direction of the slot at.v the beginning ofthe cut is about 45 degrees, and toward the. end of the cut is about 10 degrees, which further increases blades as they approach the end of the out.

In order to insure close engagement of' the blades with each other and thereby to adapt the shears to the cutting of thin metal and paper andthe like, as well as to the cutting of metal of heavy gage, the shank lO'is offset beyond the pivot 7, as, shown at'20, so that the shank 10 is in substantially the-same plane as the shank 8.

A flat spring 21 is clamped on the, pivot pin 7 betweenthe nut 22 andthe blade 5 and bears on the shank 10, in rear of its pivot, with sufficient force to maintain a close en- 1 gagement between the blades, as will be readily understood.

From the foregoing description, it will be seen that I have provided a simply con- .thepower whichmay be applied to the spirit of the invention.

What is I claimed 1. 'A pair of shears provided with a relatively line-d blade hav ng a shank terminating' in an integral handle, a relatively movable blade inter nediately pivoted there- 'to and having a relatively short shank, a secondhandle having a shank with ears secured to opposite sides thereof and extending inwardly and outwardly therefrom, the

inwardly extending portions straddling the first-mentioned shank and connected there to by a pivot pin, the outwardly extending portions oi the ears having a roller journaled between them, said 'short shank having a curved slot in which said roller rides, sa d slot extending at a progressively 1ncreasing distance from said pivot pin.

2. A pair of pivoted cozic'ting blades having shanks extending beyond the pivot, one of said shanks having an ntegral handle,

the other shank terminatingshort oi the I handle and provided with a curved slot, a second handle having ashank.terminating ,in a pair :otears which are pivoted to opposite sides of the shank of the first-mentioned handle, said ears also extending"lat; v,era lly in the opposite direction and carry inga roller .engaging'said-slot.

3. pair of shears including a fi x ed blade, a movable blade. .pivoted thereto, the

fixed blade having an integral handle, a I

second handle pivoted to the shank of the I fixed handle, saidv movable blade having a shank terminating short of the pivot of the movable handle and having a curved 5. A pair of shears blades provided with handles for actuating the same, and a flat spring secured to the pivot outside of one of the blades and bearslot with its concave side toward said pivot but eccentric thereto, said movable h'andleI having meansengaging said slot, the curvature 0t SEtiCl'SlOt increasing in radius toward the handle whereby increased power is obtained as the cut approaches the point of the shears.

4. A "pair of: shears including fixed blade, a movable blade pivoted thereto, the fixed blade having an integral handle, a second handlev pivoted to the shank of the'fixed handle, said movable blade having a shank terminating short otthe 'pivot'oi the movable handle and having a curved slot with its concave side toward said pivot but eccentric thereto, said movable handle having a laterally extending arm and a roller carried by {said arm andengagmg said slot, "the curvature of the slot increasing in radius toward the handle whereby greater power is obtained as the cut approaches the point of the shears,

including pivoted ing against the shank of the other blade between the pivot and the handle in a direetion transverse to themov'e nent of the blades to urge the cutting edges together.

-6. A' pair 01' "shears including pivoted bltlClGSlltHlllg shanks extend ng beyond the piv'otand provided" with handles, one of the shanks-being oii setfi n rear of the pivot, said otiset portion being n-the same plane as the shank of the other blade, and a-flat spring secured to the pivot outside of the lastmentioned blade and bearing against the offset shank portion in a direction transverse to thei planeof movement of the blades to urge the cutting edges together/ In testimony that I claim the foregoing as ny'own, I have hereto afiizr'ed my signa-- 'ture. Y

. I ABNER SHIRK. 

